MIC2169AYMM-TR Microchip

MIC2169A Micrel MIC2169A 500kHz PWM Synchronous Buck Control IC General Description Features The MIC2169A is a high-efficiency, simple to use 500kHz 3V to 14.5V input voltage range PWM synchronous buck control IC housed in a small MSOP- Adjustable output voltage down to 0.8V 10 package. The MIC2169A allows compact DC/DC solutions Up to 95% efficiency with a minimal external component count and cost. 500kHz PWM operation Adjustable current limit senses high-side N-Channel The MIC2169A operates from a 3V to 14.5V input, without MOSFET current the need of any additional bias voltage. The output voltage No external current-sense resistor can be precisely regulated down to 0.8V. The adaptive all Adaptive gate drive increases efficiency N-Channel MOSFET drive scheme allows efficiencies over Overvoltage protection protects the load in fault 95% across a wide load range. conditions The MIC2169A senses current across the high-side N- Dual mode current limit speeds up recovery time Channel MOSFET, eliminating the need for an expensive Hiccup mode short-circuit protection and lossy current-sense resistor. Current limit accuracy is Internal soft-start maintained by a positive temperature coefficient that tracks Dual function COMP and EN pin allows low-power shut- the increasing R of the external MOSFET. Further cost DS(ON) down and space are saved by the internal in-rush-current limiting Small size MSOP 10-lead package digital soft-start. Applications The MIC2169A is available in a 10-pin MSOP package, with a wide junction operating range of 40C to +125C. Point-of-load DC/DC conversion Set-top boxes All support documentation can be found on Micrels web site Graphic cards at www.micrel.com. LCD power supplies Telecom power supplies Networking power supplies Cable modems and routers Typical Application V = 5V IN MIC2169A Efficiency SD103BWS 100 100F 95 0.1F 4.7F 90 0.1F 85 5 80 VDD BST 1k CS 75 IRF7821 70 VIN HSD MIC2169A 2.5H 3.3V 65 2 VSW V = 5V 60 IN COMP/EN 1.4 V = 3.3V IRF7821 10k 55 OUT 150pF 100nF LSD 1000pF 0.1F 50 150F x 2 0246810121416 FB 4k GND I (A) 3.24k LOAD MIC2169A Adjustable Output 500kHz Converter Micrel, Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 474-1000 MIC2169A Micrel Ordering Information Part Number Pb-Free Part Number Frequency Junction Temp. Range Package MIC2169ABMM MIC2169AYMM 500kHz 40C to +125C 10-lead MSOP Pin Configuration VIN 1 10 BST VDD 2 9 HSD CS 3 8 VSW COMP/EN 4 7 LSD FB 5 6 GND 10-Pin MSOP (MM) Pin Description Pin Number Pin Name Pin Function 1 VIN Supply Voltage (Input): 3V to 14.5V. 2 VDD 5V Internal Linear Regulator (Output): V is the external MOSFET gate DD drive supply voltage and an internal supply bus for the IC. When V is <5V, IN this regulator operates in dropout mode. 3 CS Current Sense / Enable (Input): Current-limit comparator noninverting input. The current limit is sensed across the MOSFET during the ON time. The cur- rent can be set by the resistor in series with the CS pin. 4 COMP/EN Compensation (Input): Dual function pin. Pin for external compensation. If this pin is pulled below 0.2V, with the reference fully up the device shuts down (50A typical current draw). 5 FB Feedback (Input): Input to error amplifier. Regulates error amplifier to 0.8V. 6 GND Ground (Return). 7 LSD Low-Side Drive (Output): High-current driver output for external synchro- nous MOSFET. 8 VSW Switch (Return): High-side MOSFET driver return. 9 HSD High-Side Drive (Output): High-current output-driver for the high-side MOS- FET. When V is between 3.0V to 5V, 2.5V threshold MOSFETs should be IN used. At V > 5V, 5V threshold MOSFETs should be used. IN 10 BST Boost (Input): Provides the drive voltage for the high-side MOSFET driver. The gate-drive voltage is higher than the source voltage by V minus a IN diode drop. M9999-040609 2 April 2009